The present invention relates to autonomous vehicles, and more specifically to contextual priority signals for autonomous vehicles.
Emergency vehicles get automatic priority and can signal other vehicles in their path on the road to obtain automatic road clearance. The emergency vehicles are identified uniquely to both driver-controlled vehicles and driverless or autonomous vehicles (with some vehicle metadata property or signal) to aid the emergency vehicles in notifying the vehicles in their surroundings.
An autonomous vehicle is a vehicle that is capable of sensing its environment and navigating without human input. Autonomous vehicles detect surroundings using computer vision, radar, global positioning system (GPS), lidar, and odometry. Autonomous vehicles have systems which are capable of analyzing sensory data to distinguish between different cars on the road.
In a proposed classification by The National Highway Traffic Safety Administration (NHTSA), vehicles are classified into the following levels:                Level 0: The driver completely controls the vehicle at all times.        Level 1: Individual vehicle controls are automated, such as electronic stability control or automatic braking.        Level 2: At least two controls can be automated in unison, such as adaptive cruise control in combination with lane keeping.        Level 3: The driver can fully cede control of all safety-critical functions in certain conditions. The car senses when conditions require the driver to retake control and provides a “sufficiently comfortable transition time” for the driver to do so.        Level 4: The vehicle performs all safety-critical functions for the entire trip, with the driver not expected to control the vehicle at any time. As this vehicle would control all functions from start to stop, including all parking functions, it could include unoccupied cars.        
The Society for Advanced Engineers (SAE) has created a system based on six different levels (ranging from driver assistance to fully automated systems). This classification system is based on the amount of driver intervention and attentiveness required, rather than the vehicle capabilities, although these are very closely related. The SAE classification system includes the following levels:                Level 0: The driver completely controls the vehicle at all times.        Level 1: Individual vehicle controls are automated, such as electronic stability control or automatic braking.        Level 2: At least two controls can be automated in unison, such as adaptive cruise control in combination with lane keeping.        Level 3: The driver can fully cede control of all safety-critical functions in certain conditions. The car senses when conditions require the driver to retake control and provides a “sufficiently comfortable transition time” for the driver to do so.        Level 4: The vehicle performs all safety-critical functions for the entire trip, with the driver not expected to control the vehicle at any time. As this vehicle would control all functions from start to stop, including all parking functions, it could include unoccupied cars.        Level 5: Other than setting the destination and starting the system, no human intervention is required. The automatic system can drive to any location where it is legal to drive.        
There are situations in which vehicles which are not designated as emergency vehicles (e.g. apart from police, ambulance and fire vehicles), require temporary emergency status. For example, a personal vehicle carrying a patient requiring immediate treatment, a doctor travelling to a hospital to perform an urgent surgery or a passenger travelling to catch flight.